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[en] This series of slides present the excited states that have been identified in 116,118,120Sn using the (nth, γ) reactions on natural Sn. A 85-keV transition has been identified in 116Sn using the β decay of the I=5+, T = 54.29 mn state of 116m1In. Partial energy level schemes of Sn isotopes are given.
[en] The chirality in nuclei was largely debated in the last years, when results obtained with large gamma arrays on the best odd-odd candidates, like in the case of 134Pr, were in contradiction with the theoretical predictions. However, the results recent lifetime measurements in the odd-even 135Nd nucleus showed that the chiral conditions are best fulfilled in three-quasiparticle configurations involving 1 neutron and 2 protons in h11/2. Recent TAC+RPA and IBFM+BP calculations substantiate the interpretation of the observed degenerate doublet bands in odd-even nuclei of the A=130 mass region as chiral partners. An overview of the recent experimental results will be presented.(author)
[en] The proton emission from the ground state of mother nuclei with mass ranging 110 ≤ A ≤ 150 was measured in the early 1980's. This decay mode is observed for the odd-Z emitters beyond the proton drip line. The associated half-lives range from nano to seconds. Another decay mode -cluster radioactivity - was theoretically predicted in 1980 and discovered four years later. This is a very rare process and corresponds to the emission of a nucleus heavier than 4He, but lighter than a mass of a lighter fragment of a binary fission. The observed atomic masses of clusters are in the range 14 ≤ A ≤ 34, while the mass of a daughter nucleus is close ± 4 nucleons) to the doubly-magic 208Pb isotope. One of the most important decay modes of heavy nuclei is α radioactivity. The first explanation of this process was given by Gamow in 1928. It was assumed that emission is due to the quantum mechanical tunneling of a charged α-particle through the nuclear Coulomb barrier. We made an attempt to reproduce the half-lives for the mentioned above, 3 types of decay within the same simple formalism, based on Gamow theory. The simple formula for the half-lives is derived using the WKB theory for the penetration of the Coulomb barrier with a square well for the nuclear part. We show that using only one adjustable parameter - the radius constant - it is possible to reproduce with a good accuracy the half-lives for even-even α and cluster emitters. This simple phenomenological formalism is also extended by including the centrifugal term to describe proton emission. The adjustable parameter - the effective nuclear radius constant has the same value (1.21 fm) for all discussed decay modes. A good agreement with the experimental data is achieved. This document is composed of an abstract and the slides of the presentation. (authors)
[en] We have recently studied the Nd nuclei up to very high spins and identified several bands, which were interpreted as the manifestation of various types of collective motion: tilted axis rotation, principal axis rotation along the short and long axes, wobbling motion, chiral bands. All these types of excitation have been observed in 138Nd and are discussed in the framework of the tilted axis cranking (TAC) and cranked Nilsson-Strutinsky (CNS) models. (authors)
[en] The level structure of sup(135,137)Pr and sup(136)Pr nuclei was investigated using (heavy-ion, xnγ) reactions and in-beam γ-ray spectroscopy. New states with spins up to 23/2sup(-) were observed in sup(135,137)Pr and complete new information was obtained for the odd-odd sup(136)Pr nucleus. The odd-even nuclei can be described by coupling of the odd-proton states to the excitations of the doubly even core. The experimental data support the applicability of the triaxial rotor-plus particle model calculations and the SU(6) particle quadrupole-phonon coupling model. (author)
[en] We have recently studied the Nd nuclei up to very high spins and identified a multitude of bands which are interpreted as the manifestation of a nucleus with stable triaxial shape, presenting various types of collective motion: tilted axis and principal axis rotation, wobbling motion, chiral bands. Seniority isomers built on nearly spherical shapes up to very high spins, surrounded by coexisting triaxial bands, have also been observed. The new results obtained from the systematics of the high-spin bands of Nd nuclei are discussed. (paper)
[en] The lightest nuclei in the A = 130 mass region reachable with stable beams were investigated by using the 40Ca+92Mo fusion-evaporation reaction and the powerful detection system consisting of GASP+ISIS+n-ring at Legnaro (Italy). The level scheme of 122La was established for the first time. The observed rotational bands are compared with the bands observed in the heavier Lanthanum nuclei and possible configuration assignments are discussed
[en] The chiral interpretation of negative-parity twin bands in the odd-A 135Nd nucleus was investigated in the interacting boson-fermion model. The IBFM calculation shows that the dominant role in the formation of the chiral pattern has the exchange interaction, i.e., the antisymmetrization of odd fermions with the fermion structure of the bosons. The structure of the twin bands in 137Nd has also been investigated, concluding that it is determined by shape fluctuations and prolate-oblate coexistence rather than by chirality.